Study On Dispersive Solid Phase Extraction Of Environmental Estrogens With Ce-Doped DUT-52 Metal Organic Framework

Objectives Environmental estrogens（EEs）are extensive distribution in industry productions and daily life,but excessive EEs discharge can lead to water pollution and body lesion,effective analysis is a prerequisite for the sanitary supervision of EEs.Sample pretreatment is an indispensable part in the analysis of toxic and hazardous substances.The development of fast and simple pre-process technology can effectively concentrate the target analytes and minimize matrix interferences to further improve the analysis efficiency and reduce the cost consumption.In this study,Ce（III）doped metal-organic framework CeDUT-52 was prepared by a solvothermal method,and the material was used as high-efficiency adsorbent for the dispersive solid phase extraction（DSPE）coupled with high performance liquid chromatography-ultraviolet（HPLC-UV）analysis for determination of steroid estrogen in urine samples and bisphenols in lake and tap water.Methods 1 The doped metal-organic framework CeDUT-52 was prepared by solvothermal method.Furthermore,the material was characterized by X-ray diffractometer（XRD）,Fourier-transform infrared spectrometer（FT-IR）,scanning electron microscope（SEM）,X-ray energy spectrometer（EDS）and specific surface area and aperture analyzer,respectively.2 The prepared material was used as an adsorbent for DSPE of steroid environmental estrogens in urine samples.The experiment key factors such as the amount of adsorbent,adsorption time,the p H,Na Cl concentration,elution solvent and elution volume were optimized in detail.Under the optimal conditions,the linear range,limits of detection,limits of quantification,accuracy and precision of the method were evaluated.In addition,the reusability of CeDUT-52 was investigated,and the possible adsorption mechanism between CeDUT-52 and steroid estrogen also was analyzed.3 The CeDUT-52was further used as adsorbent for DSPE of bisphenols in water samples.The solid phase extraction conditions such as the amount of adsorbent,adsorption time,elution solvent and elution volume were investigated.The analytical figures of merit such as linear range,limits of detection,limits of quantification,accuracy and precision of the method were evaluated.Moreover,the adsorption performance of CeDUT-52 was evaluated by comparing with the commercial adsorbent C18.Results 1 XRD,FT-IR and EDS results showed that the Ce-doped metal organic framework had the main structure of DUT-52 and the Ce（III）had been doped into CeDUT-52,which confirmed the material was successfully prepared.The SEM images revealed that the CeDUT-52 and DUT-52 both had octahedral crystal structure,but the particle size of the former was smaller.The calculated BET surface area of CeDUT-52 reached 774.7 m².g^-1,and the pore volume and pore size were 0.397 cm³.g^-1 and 2.05 nm,respectively.2 A new method based on DSPE using CeDUT-52 combined with HPLC-UV had been developed and applied to analyze three estrogens in urine samples.The estrogens in urine were adsorbed completely with no more than 3 min when performing 10 mg adsorbent.The p H（4-9）and Na Cl concentration（0%-20%）of the sample had little effect on the adsorption of estrogens.0.5 m L×2 of methanol was used to desorb target analysis by stirring for 10 min.Under the optimized conditions,the developed method showed good linearity in the range of 5-500 ng.m L^-1（r≥0.9995）,low limits of detection(1.5-2.0 ng.m L^-1).The recoveries of spiked estrogens in urine samples were 79.8%-96.1%and relative standard deviations（RSDs）ranged from 2.4%to 5.9%,the satisfactory enrichment factors could reach to 26-28.The RSDs for estrogens in urine were less than 4.8%in 6 successive cycles of extraction/desorption of CeDUT-52.Hydrophobicity,hydrogen bonding andπ-πinteraction were the three important mechanisms for adsorption of the analytes on CeDUT-52.3 Three bisphenols in water were pretreated by using CeDUT-52.As 50 m L of sample was taken,the adsorption could be achieved by applying 40 mg of adsorbent within 20 min,and 0.5m L×3 of methanol was used as desorption solvent,and the elution time was 10 min.Combined with HPLC-UV,the method processed a good linearity in the range of 0.3-600μg.L^-1（r≥0.9998）,and the limits of detection were 0.1-0.2μg.L^-1.The recoveries of the method were from 82.5%to 100.7%.Intra-day and inter-day RSDs were less than 6.3%and10.5%,respectively.The adsorption capacity of CeDUT-52 was equivalent to that of C18.Conclusions 1 In this study,CeDUT-52 was prepared by solvothermal method as an adsorbent for DSPE coupled with HPLC-UV for determination of steroid estrogen in urine samples.The method could complete the adsorption within 3 min,and provided the enrichment factor of 26-28.Furthermore,the adsorbent could be reused at least 6 times under the conditions.Therefore,the method had a good application prospect in the analysis of steroid estrogen in urine for its fast,accurate and economical performance.2 The prepared adsorbent was used for determination of bisphenols in environmental water.As the sample volume was 50 m L,the enrichment factors could reach 92-102.The developed method was fast and sensitive,which met the requirements for the analysis of bisphenols in water.Figure 21;Table 13;Reference 156...